Stimulation of neural tissue may be an effective treatment for a variety of physiological and psychological conditions. For instance, neural stimulation may be used in cochlear implants to provide functional hearing for deaf patients as well as in visual prosthetics (e.g., retinal implants) to restore vision. Pacemakers may also rely on neural stimulation to control and prevent incidents of, for example, cardiac rhythm irregularities (e.g., tachycardia), heart failure, and stroke. The technology may further be employed for brain stimulation to treat, for example, epilepsy, Parkinson's disease, and a variety of affective disorders (e.g., depression, obsessive compulsive disorder, chronic pain).
Conventional neural stimulators require wired connections between the electrodes and a separate power source. The bulk and weight of a typical power source (e.g., battery) prevents the power source from being implanted along with the neural stimulator. But keeping the power source external may tether a patient to the power source during treatment. This restriction in patient mobility may prevent treatment from being administered to the patient over an extended period of time. Treatment also may not be available to the patient as and when needed. Thus, conventional neural stimulators may be unable to effectively treat conditions with chronic and/or unpredictable symptoms (e.g., sudden onset of epileptic seizure). Moreover, the delivery treatments via a conventional wired neural stimulator may require invasive procedures (e.g., incisions to accommodate the wired connections), which may elevate a patient's risk of infection.